Explosive charge for guns or other uses.



N0. 7l6,768. Patented Dec. 23, [902.

R. W. SCOTT. V EXPLOSIVE CHARGE FOR GUNS OR OTHER USES.

(Application filed May 31, 1901.)

2 Sheets-Sheet I.

(No Model.)

HHIWIWIIHIW N0. 7|6,768. Patented Dec. 23, [902.

R. W. SCOTT.

EXPLOSIVE CHARGE FOR GUNS OR OTHER USES.

(Application filed May 31. 1901) (No Model.) 2 Sheets-Sheet 2.

%V///////////////I/////////%f ing my invention.

UNITED I STATES PATENT, OFFICE. I

ROBERT W.'SCOTT, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF ONE- HALF TO' LOUIS N. D. WILLIAMS, OF ASHBOURNE, PENNSYLVANIA.

EXPLQSIVE CHARGE FOR GUNS OR OTHER USES.

' srEcIFIc rroN formingpart of Letters Patent No. 716,768, dated December 23, 1902.

1 p Application filed May 31, 1901.

To all whom it may concern.-

Be it known that I, ROBERT W. SCO'1T, a citizen of the United States, residing in Philadelphia, Pennsylvania, have invented certain 5 Improvements inExplosiveCharges for Guns or other Uses, of which the ,following is a specification.

The object of my ipvention is to provide an explosive charge designed to generate gas under moderat'epressure at the beginning of combustion and then to increase the'volume of gas, whereby if said explosive charge is intended to be used in a gun high velocity will be imparted to the projectile without gen- 1 r5 crating such high pressure in the chamber of the gun as to incur any risk of straining or bursting the same;

In the accompanying drawings, Figure 1 is a sectional view of a gun-cartridge embody- Fig. 2 is an enlarged ,side

view of part of a strand of explosive material prepared for producing the units of the charge of said cartridge. Fig. 3 is a transversesection of one of the completed units. Figs. 4. to 16 are views of other forms of explosive charges or units embodying my invention, and Figs. 17 to 22 are views illustrating various methods of making explosive charges in accordance with my invention.

y Heretofore in order to overcome the inertia of a projectile with the least possiblestrain on the chamber of the gun grains or. lumps of powder of the largest possible size have been used and shapes'such as prisms or tu- 5 bular forms have been resorted .to in order to provide a superficial area decreasing as slightly as possible in proportion to the mass as each grain or lump was being consumed; but alimit in this direction is quickly reached, 40 for if the grains or lumps of powder are too, large,and consequently slow of combustion,it

- is impossible to obtain the desired velocity fin the projectile, while if they are too small the chamber pressures will be excessive. 5" Even when composite charges are resorted to -that is to say, charges wherein large-sized grains are first seated next to the means of ignition and then smaller grains, and so onbut little if any advantage is secured, as the ignition of such a charge is practically simulstarting.

Serial No. 62,665. (No model.)

and it is now well established that combustion goes on regularly-from the outside toward the center of such combustible body, With these facts in mihd I have devised an explosive charge in which when the charge is first ignited the combustion will be relatively slow, and the projectile will therefore be started in its movement through the bore of the gun with comparative gentleness; but when the projectile is well under way the charge will burn quickly,the effect being that the chamber-pressure is materially reduced and the strains are distributed throughout the bore of the gun. HenceI am enabled to secure the ordinary velocity with reduced strain upon the gun, or with the ordinary pressure I am enabled to attain increased velocity of projectile, vand, furthermore, 0w-

ing to the gentleness withwhich the movement ofthe projectile is started, said pro jectile maybe made in the form of a shell with high-power bursting charge without danger of being burst in the gun by the'shock of s In Fig.1 of the drawings the metallic case of an ordinary smallarm cartridge is shown at a, the projectile at b, and my improved projecting charge at d. The charge may consist of any of the nitro powders now used or any ex- 0 plosive material containing in itself the elements necessary for its combustion and capable of developing by such combustion the desired degree of power. I .In making the charge shown in Figs. 1, 2, 5 and 3 a strand of comparatively large size is employed, the diameter or crosssectional area of the strand, in fact, being so great that if it were cut into pellets having a length equal to the diameter-or cross-section without fu-rtco five cuts to the inch, and in order that the' ther treatment said pellets would be only partially consumed in the bore of the ordinary small-arm. Consequently the contained energy would not be utilized and the velocities and pressures attained would be low. In or,- der, therefore, to secure the advantage of the low pressure of such a charge and at the same time obtain desirable velocity in the projectile, I divide the strand into thin slabs or flakes. For instance, supposing the strand to be .075 of an inch in diameter, I cut the same so as to form slabs or flakes of about .013 of an inch thick, or at the rate of seventy strand may be handled with facility the incisions which form these slabs or flakes do not pass entirely through the strand, but leave a portionsay about one-eighth of the entire mass-uncut, as shown, for instance,at l in Fig.3. After having the incisions formed therein, as shown, the strands are by preference passed through a solution of the nitropowder composition or other combustible gasproducing material containing the elements necessary for its combustion, such being referred to hereinafter simply as solution, or in some cases the strands may be simply passed through a bath of a suitable solvent, such as acetone or a mixture of ether and alcohol, depending on the chemical composition of the material, this solvent serving to soften the strand on the exterior, so that contiguous surfaces become united and asealed film or barrier is formed over the mouths of the nicks in the strand.

The film or barrier not only provides a hermetically-sealed closure or envelop for the nicked strand, but it unites with or forms part of the material of the strand, and hence will prevent access of the flame to the surfaces of the slabs or flakes until after the, film is consumed, still freer access of the flame being permitted when the portion 1 of the strand has been burned away, so as to permit the slabs or flakes to fall apart.

The protecting film or envelop formed by passing the strand through the solution is shown at 2 in Fig. 3. ulated the strand into pellets about one-eighth of an inch long, so that each pellet will be composed of nine flakes, presenting a superficial area increased by sixteen times the area of one end of the pellet as soon as the film or barrier 2 and the connecting-web 1 are destroyed and the flakes permitted to separate one from another. A pronounced advantage of this form of unit is that it is granulated fine enough to be fed in the usual manner through the ordinary loading-machine now in use in the Government arsenals and ammunition factories, and the charge can be weighed or measured to a nicety, whereas when a series of strands or a single rod or bar is used, as has been proposed, accurate charging is impossible, even in the arsenals and factories. Thegranularformisespeciallyad- In practice I have gran- 'vantageous when used in cartridges for shotguns or rifles for target or sporting purposes,

area when the coating has been consumed is the average of all of the pellets, which will be about the same in all of the cartridges, whereas this relation in individual pellets or strands may vary somewhat, and therefore lead to irregular results when such individual pellets'or strands or a few of them constitute the entire charge. v

Experiments with a chronograph show that a thirty-six-grain charge of pellets formed from the strands before being treated in accordance with my invention gave a mean observed or instrumental velocity of but fourteen hundred and seventy-five feet per second, while a charge of the same weight treated in accordance with my invention and used in connection with the same weight of projectile as before gave a'r'nean instrumental velocity of twenty-one hundred and fifty feet per second, indicating consumption of the charge in one case and not in the other. Moreover, by providing the nicked pellet with a protecting-film the rate of combustion at the beginning is no greater than in the case of the solid pellet. Consequently the projectile is started in the bore of the gun with comparative gentleness, and when the remaining gas-producing surfaces are attacked the projectile is moving and a larger and constantlyincreasing space is afforded for the complete combustion of the charge and expansion of the resulting gases. Hence the pressure in the chamber of the gun is but slightly greater than'when the solid pellet is "employed.

Instead of forming incisions in the strand, as shown in Figs. 2and 3, I may in some cases form a continuous spiral incision, as shown in Fig. 4, leaving a small central core 3, this plan having the advantage of producing a stronger strand, owing to the presence of the central core, and having the further advantage of being produced by an operation involving rotary motions only, with consequent greater production.

In some cases the strands may be slitted longitudinally-as, for instance, by drawing them through a die having inwardly-projecting knives, such as shown at 4 in Fig. 18, these knives projecting into the die suffieiently to leave a small core of the strand uncut at the center of the same, this strand being coated with a surface film of the solution, and the ends of the pellets cut from the strand being subsequently provided with a similar film, as also are the pellets shown in Fig. i.

' An explosive unit in accordance with my invention maybe made by first rolling the material in the form of thin sheets of the thickness desired for a flake, a number of these sheets being then stacked one on top of another, as shown in Fig. 19, and then subjected to pressure tending to force them together, while the edge 5 has a coating of the solution vor solvent applied thereto, whereupon a strip may be cut ed at the end of the slab by a knife cutting on the line 6, so as to producea strip consisting of a series of long flakes held together by the edge film, this strip being subsequently severed into smaller pieces, as by knives cutting on the lines 7, which, however, do not sever the bottom strip, the latter serving to hold the several pellets together, but being susceptible of bending, so as to separate said pellets while they are dipped in the solution, thereby insuring the coating of the same on all sides, the pellets being then separated by cutting the bottom strip, whereby a completely enveloped unit with any desired number of subdivisions results.

Other means of making a composite unit or pellet from the sheets of material may be resorted to. For'instance, the layer of sheets may be much thicker than is suflicient for a single unitor pellet and, being united by a film on the edge 5, may be completely severed on the dotted line 6 and likewise entirely separated on each of the lines 7, the elongated strips then being dipped or passed through the solution and finally granulated into units containing the desired number of slabs or flakes.

The forms of pellets shown in Figs. 2 and 3 may be made by a vibrating knife operating in conjunction .with a suitable feeding apparatus for the strand, or a pellet having a central web of the material left standing as, for instance, at 9, in Fig. 20 -may be produced by a vibrating cutter having spaced knives, such as 'shown at 10 in said figure, adjustment of the knives from and toward each other resulting in the PIOdltCtlOH of a web of any desired thickness.

The web 1, which unites slabs or flakes in a unit of the character shown in Figs. 2 and 3, may, if-desired, have a central rib formed thereon, as shown at 11 in Fig. 21, by forming a nick in the knife 12, which produces the incision, and a pellet having acentral core, such as shown at 13 in Fig. 22, may be produced by nicking both of the cutting-knives and moving the latter so that they will meet at the center of the strand.

A central rib, as shown in Fig. 20, or a central core, such, as shown in Fig. 22, permitsthe strands to be readily coiled in long lengths and to be handled without danger of either fracture of the enveloping film or breaking of the strand.

In the case of a nicked or subdivided pellet access of the flame to the surface of the subdivisions may be delayed by passing the cord or strand after it has been nicked or slotted through a solvent of the'material of which the strand is composed and thenthrough a die of suitable size, for the cutting-knife, however keen, will raise more or less of a ridge or bur of the material about the mouth of the incision, and this bur when softened by. the

solvent and pressed down by the die will provide a hermetically-sealed covering for the mouths of the incisions. I

When'it is desired to increase the superficial area of the charge at more than one stage as combustion proceeds, the unit or pellet may be made as'shown in Fig. 5, the strand being first slitted at the rate of, say, thirty incisions to the inch, then enveloped with a coating 14 of the solution, then again slitted at the same rate, the incisions occurring'oneninetieth of an inch from the first, then again given an enveloping coating 15, and finally slitted again 1n the centers of the remaining spaces and again coated, as shown at 16, so

that when the first film is destroyed access is had to one-third of the incisions. When the second film is burned away another one-third of the incisions is presented to the action of the flame, and when the last film is consumed all of the gas-producing surfaces are supplying energy, and, if desired, the successive sets of incisions may be of difierent area, as shown, for instance, in Fig. 6. v

Slabs or disks of the material maybe united by means of films 17 of the solution, which films are of various depths or degrees of penetration between the disks, as shown in Fig. 7, partof the internal combustion-surface being thus exposed when the shallowest films have burned away,other portions of said inter; nal combustion-surface being exposed when the next deeper films have been consumed, and so on until all of the internal combustionsurfaces are ignited.

I In the units shown in Figs.'5 and 6 the first set of incisions form one member of a group and are closed bythe single thickness of film 14, the second set form the second member of the group and are closed by a double thickness of film 14 15, and the third set form the third member of the group and are closed by a triple thickness of the film 14 16, and'in the unit shown in Fig. 7 the internal surfaces of like area form one member of the group, the sealing-film presenting three different degrees of resistance to the action of the igniting-flame.

It' will be apparent that when the units are formed of slabs, flakes, or disks, as described,

the pressure exerted by the combustion of the external surfaces cannot breakdown the slabs, flakes, or disks composln g the units, as might be the case if units of hollow form were employed; but even in the latter case, especially when the openings have been closed coating of the strand may therefore be adopted ICO in carrying out my invention. Thus in Figs. 8 and 91 have shown a unit consisting of a bunch or group 20 of cords or strands of small diameter enveloped within a casing 21 of explosive material forming a hermeticallysealed envelop, which is united with the outer cords of the bunch or group, and in Figs. 10 and 11 I have shown units composed of perforated' blocks or slabs 22, provided with envelops 21 of the same shown in Figs. Sand 9.

The envelops shown in Figs. 12 and 13 are in the form of sealed casings containing the grains, flakes, or other forms of unit of the explosive charge, the envelop in the charge shown in Fig. 12 consisting of a deep cup 23 ofcombustiblegas-generatingmaterial,sealed at one end by a head 24 of similar material, which is united to the material of the cup, while in the charge shown in Fig. 13 the cup 25 has its ends overlapped and united together, it being essential to all of these forms of my invention that the barrier which protects the internal combustion surface or surfaces of the charge or unit from the flame shall present no joint or aperture through which the igniting-flame can pass, otherwise the purpose of the envelop or barrier would be defeated.

The union of the meeting edges of the elecharacter as that ments of the envelop shown incFig s. 12 and 13 can be readily effected by rendering such meeting portions plastic by means of a solvent of the material of which they are composed and then pressing said meeting portions together while they are in this plastic condition. his not, however, essential to the proper carrying out of my invention that a continuous sheath or envelop should be employed to retard access of theflame to the internal combustion-surface of the charge or unit. For instance, in Fig. 14 I have shown a tubular unit 26, in which the barrier consists simply of plugs or wads 27 of combustible material hermeticallyclosing the ends of the central opening of the unit and united to the walls of said opening, or the ends of the tube may be sealed by simply-dipping the same in the solution, so as to form sealing-films over the opening, and a unit 28, having a multiplicityot' openings therein, may be treated in thesame wayas shown, for instance, at 29 in Fig. 15.

A convenient means of closing the ends of the openings in perforated grains, pellets, or units is shown in Fig. 17. As the tubular strand issues from the die and is still in plastic condition it may be subjected at suitable intervals to a contracting pressure, which will close the opening or openings in said strand and unite the walls of the said opening or openings so as to seal the latter at the required intervals, the strand being subsequently severed at these sealed portions.

In Fig. 16 I have shown a composite form of gun charge adapted for use in large-caliber guns. In this view, 30 represents anumberof units similar to those shown in Fig. 5, or which may be any of the other forms of unit illustrated, the bundle or fagot of these units being contained within a sealed sheath or envelop 31 of combustible gas-generating material, and a number of these sheathed or enveloped fagots being contained within a general sheath or envelop 32, forminga sealed casing or covering for the series.

It will be observed that the internal combustion-surface in all cases is of predetermined definite area and that the sealed barrier of readily-ignitible material forms a substantially integral union with the material of the unit.

By the use of a number of comparatively slow-burning envelops in this manner the generation of pressure can be closely regulated, there beinga grad ually-increasing area of combustion, owing to the gradual increase of superficial area in proportion to mass.

In the case of a cartridge prepared in accordance with my invention and intended especially for small-arms where a jacketed bullet is employed greater accuracy in the flight of the bullet will be attained, because there is not that distortion of the bullet which ordinarily takes place when it is subjected to the usual enormous pressure before its inertia is overcome, and the erosion of the lead or entrance to the ritling of the gun will be prevented. Moreover, bullets without the hard-metal jacket may be used, as their movement into the quick-twist bore will be started at such greatly-reduced pressure that they will not be nearly so apt to jump the rifling as is the case where a lead bullet is used in quick-twist bores and the chamber-pressures are excessive.

' A projecting-charge made in accordance with my invention is of pronounced advantage in connection with a multishot ball-cartridge where the aggregate weight of the projectiles is necessarily in excess of the weight of the regular or service ball and both the single and multishot cartridges are intended to be used interchangeable in the same arm. Hence the pressures and velocities should be, as nearly as may be, alike.

Some of the forms of charge shown-for instance, that of Fig. 7-are peculiarly well adapted to guns of large caliber.

It will of course be evident that the sheath, envelop, or other barrier which I use for temporarily protecting the quick-burning portion ICC of the charge is distinct from a wad of paper or such like material, as it contains within itself the elements necessary to sustain combustion in a confined space, whereas a more paper wad is not combustible without the access of oxygen from some source other than itself,'and hence would not burn readily in the confined cartridge-chamber of a gun. It will also be evident that my invention is distinct from an explosive element consisting of crease in the volume has no internal combustion-surface in addition to its external combustion-surface and the greater rapidity of combustion of the contained slab or disk is counteracted either wholly or in part by the constantly-decreas-- ing area of the surface exposed for combustion, whereas my unit exposes a greater sur-. face for combustion as soon as the barrier or envelop is burned away.

Myinvention is also distinct from that form of explosive unit which consists of a block or slab having perforations or cells the ends of which are closed by a disk or washer or by some other portion of the block or slab which merely forms a contact-joint, asexperience has demonstrated that no such contact-joint afiords an appreciable barrier to the products of combustion developed in the burning'of modern gunpowders.

. Although I have described my improved explosive charge as applied to gun-cartrid ges, it will be evident that it is equally adapted for use in'explosive-engines, gunpowder piledrivers, and the like.

The term explosive unit as used in the claims applies to all of the forms illustrated, whether such unit constitutes a complete charge or only an element of the charge.

It should be understood that the explosiveenvelop, whereby the internal combustionsurfaces of an explosive unit made in accordance with my invention are hermetically sealed, is readily ignitible, and hence is distinct from a.celluloid varnish such as has been proposed as a coating for explosive charges of guns and which is intended to form a waterproof coating that is difiicult of ignition.

It willbe noted that the outer peripheral surface of each of the explosive charges or units which I have illustrated. is the one which is first ignited, and the area of this surface bears such relation to the area of the internal combustion-surface exposed when the barrier between the two has been burned away that there will not at that time be such undue augmentation of the area of the combustion-surface a s of gas generated, with accompanying dangerous increase of. pressure.

Having thus described my invention, I claim and desire to secure by Letters Patcut-- 1. An explosive unit for generating moderate initial pressure,.said unit having an internal combustion-surface of definitepredetermined area in addition to the external peripheral combustion-surface and ahermetically-sealed barrier of readily-ignitible explosive material temporarily protecting said internal combustion-surface from access of the igniting-flame whereby access of the flame ternal combustion-surface in to lead to a dangerous in-' to said internal combustion-surface is prevented until said barrier is burned through.

2. An explosive unit for generating moderate initial pressure, said unit having an internal combustion-surface of defined predetermined area in addition to the external peripheral combustion-surface and a hermetically-sea'led barrier of readily-ignitible explosive material which forms a substantially integral union therewith at the points of contact and temporarily protects said internal combustion-surface from access of the igniting-fiame.

3. An explosive unit for generating moderate initial pressure, said unit having an internal combustion-surface of definite predetermined area in addition to the external combustion-surface and a hermetically-sealed envelop of. readily-ignitible explosive material containing saidunit, whereby access of the flame to said internal combustion-surface is prevented until the barrier formed by said envelop has first been burned away.

' 4. An explosive unit for generating moderate initial pressure, said unit having an inaddition to the external combustion-surface and being provided with a hermetically-sealed envelop of readily-ignitible explosive material, which envelop forms a substantially integral union therewith at the points of'contact.

5. An explosive unit for generating moderate initial pressure, said unit having a series of subdivisions connected so as to prevent separation until the connection has been burned awayv and being provided with a barrier of readily-ignitible explosive material which hermetically seals the spaces between said subdivisions and prevents access of the igniting-flame thereto until it has been burned away.

6. An explosive unit consisting of, a strand having therein a series of incisions which extend only part way through the strand, and a film of readily-ignitible explosive material which hermetically seals the mouths of said incisions.

7. An explosive unit presentinga group of internal combustion-surfaces and a hermetically-sealed barrier of readily-iguitible explosive material temporarily protecting each member of the group from ignition, said barriers difieriug in extent whereby the difierent members of said group of internal combustion-surfaces will be exposed to ignition at difierent stages of combustion.

8. An explosive unit having a group of-internal comlmstion-surfaces varying in area and a hermetically-sealed barrierof readilyignitible explosive material temporarily protecting each member of the group from ignition, said barriers differing in extentwhereby the members of the group of internal combustion-surfaces will be exposed to the igniting-flame at different stages'of combustion.

9. An explosive unit having-a group of internal combustion-surfaces, a hermeticallysealed envelop of explosive material temporarily protecting each member of the group from ignition, and a hermetically-sealed envelop of explosive material common to all and temporarily protecting the envelop members of the group.

In testimony whereof I have signed my name to this specification in the presence of two'subscribing witnesses.

ROBERT W. SCOTT.

Witnesses:

E. BECHTOLD, J 0s. H. KLEIN. 

